SimCity yields a bit more to building management and economics while Cities XL leads more to the building of pretty cities. Both are still very fun and I have personally spent way to much time on Cities, but know that SimCity 2013 is out I'm getting drawn back into it way too much.

Anybody out their play both and can offer opinions?

I've played both and like them both quite a bit. I think I like the new SimCity a bit more though, I really like the multiplayer connectivity aspect of it. However, the game is a bit buggy right now and the servers haven't been too reliable yet. After a week or two I think the game will be really solid.

I find it funny that EU got 3 extra servers before NA (with arguably more players) got any. Biggest disappointment with me is that with Diablo 3 you knew you couldn't play at all. With SimCity you never know when you can because they have full servers or servers with trash can level connectivity.